Compression claw to connect wire meshes or wire netting, and a device to close the compression claws

ABSTRACT

A compression claw for connecting wire meshes or wire nets consists of a corrosion-protected wire and two legs ( 12, 13 ) projecting away from a rounded base ( 11 ), enclosing each other at an apex angle (α). The legs are each provided on their free end with hooks ( 16, 17 ), which are oriented away from each other. These legs ( 12, 13 ) lie in two planes enclosing an angle, such that they can move past each other when the compression claw closes. The wire is a heavy-duty steel wire. A device serves to close the compression claws  10.  This has a clamping device ( 25 ) functionally linked with a drive and clamp elements ( 30, 31 ) for the closure of individual compression claws ( 10 ), in which the compression claws ( 10 ) can be individually positioned before closure. This device allows simple and fast installation of such compression claws.

The invention concerns a compression claw to connect wire meshes or wire netting, and a device to close the compression claws.

Compression claws are used, for example, to connect mesh sheets or individual wire netting parts. They are made of a corrosion-protected wire, usually galvanised, and each have two legs projecting away from a rounded base, enclosing an apex angle, said legs each being provided on their free end with a hook, the two hooks being oriented away from each other. The compression claws are produced from a wire with a diameter of 6 mm.

Pincers are used to close the compression claws. The manual closure of the loose compression claws after threading up the respective compression claw is time-consuming. Also, the zinc coating is often damaged by the pincers, so complete corrosion protection is no longer guaranteed. Not least, the compression claws formerly used with a diameter of 6 mm are very heavy.

The present invention is based on the problem of creating compression claws and a device to close these compression claws with which installation is substantially simplified.

This problem is solved according to the invention by a compression claw with the features of claim 1 and also a device to close these compression claws according to the features of claim 7.

Further preferred embodiments of the inventive compression claw and of the inventive device form the subject matter of the dependent claims.

According to the invention, the compression claws are made from heavy-duty steel wire, and enable non-positive connection of wire meshes or wire netting which are also made from heavy-duty steel wire. Compression claws of this type are considerably lighter in weight by comparison with ordinary compression claws. The two legs lie in two planes enclosing an angle and their hooks can be moved past each other using the inventive device during closure, so that in closed condition they abut as closely as possible.

The inventive device to close compression claws allows for simple installation, in which not only the application of force, but the use of pincers, is no longer necessary, and also the chipping of corrosion protection during closure is largely prevented. With the magazine for compression claws which is preferably included, the problem of loose compression claws hooking onto each other is also solved, which further simplifies installation.

The invention will next be described in more detail with the aid of the drawings, which show:

FIG. 1 a, 1 b an inventive compression claw for connecting wire meshes, in an original condition;

FIG. 2 a, 2 b, 2 c the compression claw in closed condition;

FIG. 3 diagram of a slope stabilisation system with two sheets of mesh connected together;

FIG. 4 an inventive device for closure of compression claws in lateral view and partly in section, in an initial position;

FIG. 5 in lateral view, the device from FIG. 4 with insertion of a compression claw in a clamping device;

FIG. 6 an attachment of the device according to FIGS. 4 and 5 respectively to be affixed to a drill, in perspective view, with a magazine, a compression claw feed device and the clamping device;

FIG. 7 the attachment according to FIG. 6 in lateral view and partly in section, in the original position corresponding to FIG. 4;

FIG. 8 the attachment according to FIG. 6 in lateral view and partly in section, in the position corresponding to FIG. 5; and

FIGS. 9 to 14 the compression claw clamping device in top view, in six consecutive positions.

FIG. 3 shows, purely diagrammatically, a stabilisation system for slopes and unconsolidated material 1 for a slope 2, located for example on a steep declivity. The stabilisation system for slopes and unconsolidated material 1 consists of two wire mesh sheets 3, 4, laid out over a desired sloping area, said sheets being connected together in a way described below and according to the invention by means of a number of compression claws 10. The wire mesh sheets 3, 4 are preferably meshes made from individual heavy-duty steel wires, such as for example those known from EP-B-0 979 329. At the upper and lower end of the mesh, cables 5 are provided, by means of which the mesh is stretched by a tensile force. The wire mesh sheets 3, 4 laid out on the ground are fixated by fixing elements 6 sunk into the ground (soil or rock nails known in the art) and the mesh is pressed onto the earth's surface by spike plates 7 or similar.

According to the invention, the compression claws 10 are made from the same heavy-duty steel as the wire mesh sheets 3, 4 (nominal strength preferably at least 1770 N/mm²). The corrosion protection is also identical to that of the heavy-duty steel wire mesh (e.g. Zn/Al galvanisation, min. 150 g/m²). Where the steel wires of the meshes to be linked have a diameter of 3 mm, compression claws with a wire diameter of 3 mm are also used.

The compression claws 10 in original condition preferably have a shape which can be seen from FIGS. 1 a and 1 b, their geometry being selected such that in each case two wires of the meshes of adjacent sheets of mesh 3, 4 to be connected together can be simply grasped by direct insertion, without rotational or threading movement. The compression claw 10 in each case has two legs 12, 13 projecting away from a rounded base 11, enclosing each other at an apex angle α, preferably of 60°, which are each provided on their free end with a hook 16, 17. The two hooks 16, 17 are oriented away from each other. The two legs 12, 13 are preferably arranged at an angle γ of 14° with respect to each other immediately in front of the hook (16, 17), so that they enclose an apex angle of approximately 32° in this area.

The radius R₁ of the base interior and the radius R₂ of the hook interior are selected such that the two wires of the meshes of adjacent wire mesh sheets 3, 4 to be connected can be grasped when the compression claws 10 close. In this case, the radius R₁ of the base interior is advantageously approx. 4 mm., and the radius R₂ of the hook interior is approx. 1.25 mm. The radius R₂ of the hook interior is crucial to a non-positive connection of the wire mesh sheets 3, 4. If this is approx. 1.25 mm, when the mesh becomes stressed, sufficient friction can be mobilised to prevent the hooks 16, 17 from lifting.

The two claw legs 12, 13 lie in two planes enclosing an angle β of approx. 8° to each other so that both hooks 16, 17 can move past each other when the compression claw closes and in closed condition abut as closely as possible (cf. FIG. 3 c).

The closure of the compression claws 10 in the form shown in FIGS. 2 a, 2 b and 2 c occurs by means of an inventive device 20, an embodiment of which is shown in FIGS. 4 to 14 and which is described in more detail below.

According to FIG. 4, the inventive device 20 includes a drive element, which is advantageously in the form of an ordinary commercially-available drill 21, and an attachment 22 which can be affixed to the drill 21, which is also shown in FIGS. 5, 6, 7 and 8, and which has a magazine 23 containing a number of compression claws 10, a clamping device 25 to close the compression claws 10 and a feed device 24 to feed the compression claws 10 to the clamping device 25. The clamping device 25 has a drive connection with the drill 21 and its spindle 27 via a step-down gear 26 housed in the attachment 22 and has clamping elements 30, 31 closing the individual compression claws 10, the precise design and function of which will be explained in more detail further on. The clamping elements 30, 31 are arranged parallel to a drive axle 27 a (FIGS. 7 and 8) which can be connected to the drill spindle 27.

According to FIG. 5 (also FIG. 1), the feed device 24 has a ram 34, movable in a feed plane, which is manually operable via an actuation element 33, and co-operates with a spring 35 (FIGS. 5, 7 and 8). The feed plane is arranged parallel to the drive axle 27 a. The ram 34 can be moved out of the original position shown in FIGS. 4 and 7 against the force of the spring 35 into the position shown in FIGS. 5 and 8, thereby picking up a compression claw 10 positioned at a magazine outlet 38 located directly above the feed plane and carrying it to the clamping device 25. After that, the ram 34 is moved back again by the force of the spring 35.

The magazine 23 has a part 37 parallel to the feed plane and at a distance therefrom, in which the compression claws 10 are arranged in alignment with each other and approximately perpendicular to the feed plane, and on which a reversing part 39 abuts, by which the compression claws 10 are fed to the magazine outlet 38 lying directly above the feed plane and are brought into the feed position. The compression claws 10 are forced towards the magazine outlet 38 by means of an adjustment element 40, guided by means of pins 40′ in longitudinal grooves 37′, which co-operates with a spring 41. In the embodiment shown, the spring 41 is in the form of a tension spring and arranged underneath the magazine part 37 parallel to the feed plane. The longitudinal grooves 37′ are provided with a rounding at the rear end in order to be able to draw the adjustment element 40 back into a loading position.

As can been especially clearly from FIG. 6, the magazine 23 has a guide channel 45 corresponding in cross-section to the external form of compression claws 10. Side walls 46, 47 of the adjustment element 40 forming a V-shape enclose the angle α corresponding to the apex angle of the claw legs 12, 13. The magazine 23 is also equipped with a retaining element 48 projecting from above into the guide channel between the hooks 16, 17 of the compression claws 10, which secures the compression claws 10 in the guide channel 45 against falling out of the magazine 23.

The compression claws 10 located directly at the magazine outlet 38 are held in their position, for example by a magnet, until the impact of the ram 34, thus the other compression claws 10 are secured against premature falling out of the magazine 23.

Next, the clamping device 25 will be described in more detail and its function explained with the aid of FIGS. 9 to 14. The clamping elements which close such a particular compression claw 10 are formed firstly by a stationary clamping jaw 30 and secondly by a carrier element 31, which pivots about an axis (FIGS. 4 and 9). The carrier element 31 is provided, in accordance with FIGS. 9 to 14, with a toothed segment 50 via which, in co-operation with a toothed counter-segment 51 drivable in the direction of rotation D via the step-down gear 26, can be pivoted in a direction of rotation D₁. Arranged coaxially to the swivelling axis A is a cone-shaped peg 53 which expands in diameter towards its base. The compression claw 10 to be closed is moved by means of the ram 34 with its base interior up to the peg 53 and positioned on a ring magnet 54 coaxial to the peg 53, while the hook end of the one claw leg 13 comes to rest on a further magnet 55 assigned to the stationary clamping jaw 30 and positions the compression claw 10 (cf. FIG. 10). The claw leg 13 is supported laterally on a supporting surface 57 assigned to the stationary clamping jaw 30, which is provided with a groove-shaped recess 58 corresponding to the diameter of the compression claw 10.

A cylindrical carrier part 60 with a circumferential groove 61 (FIG. 6) corresponding to the diameter of the compression claw 10 is attached to the pivoting carrier element 31, and said carrier part, as the carrier element 31 is pivoted via the toothed segments 50, 51 in the direction of rotation D₁ as in FIG. 11, grasps the leg 12 of the compression claw 10 positioned in the clamping device 25 and presses it against the other, supported leg 13. The groove-shaped recess 58 and the circumferential groove 61 support the action of the magnets 54, 55 and prevent the compression claw 10 from “springing open” as it closes.

As can be seen from FIGS. 12 and 13, the two claw legs 12, 13, with their hooks, are now moved past each other under the co-operation of the two toothed segments 50, 51 and forced into the position shown in FIG. 13. As soon as the last tooth of the toothed segment 51 disengages from the driven toothed counter-segment 50, the compression claw 10 relaxes and adopts the final shape shown in FIG. 14, while the carrier element 31—supported by a torsion spring coaxial to the axis A (not shown in the drawing)—is pivoted back into the initial position according to FIG. 9, in which it is now ready to close another compression claw 10.

The closed compression claw 10 obviously remains in the mesh (in FIGS. 10 to 14 the meshes to be connected are not shown). The installer can feed a further compression claw 10 from the magazine 23 by the actuation element 33 to the clamping device 25 which is now clear, then take hold of the wires to be connected, bring in the device 20 and switch on the drive, in order to carry out a further closure procedure.

The inventive device 20 could, however, also cover only e.g. the clamping device 25 described above or a similar one, in which the compression claws 10 would be inserted by hand. In order to prevent the risk of loose cartridges hooking onto each other, rendering assembly more difficult, a separate magazine could also be used, which the installer could for example wear on his belt.

The use of the inventive compression claws 10 and of the inventive device 20 to close these is by no means restricted to the connection of mesh sheets used in slope stabilisation systems. The compression claws and the device can for example also be used in wire netting, such as e.g. catchment nets for rock falls and avalanche barriers, which consist of interlocking elements.

The inventive device for closing compression claws allows for simple installation, in which not only is the application of force, as with the use of pincers, no longer necessary, but chipping of the corrosion protection during closure is largely prevented. With the preferred use of a magazine—separately or as part of the device—the problem of interlocking of loose compression claws is also solved.

According to the invention, the device can also close compression claws made from heavy-duty steel wire, and enable non-positive connection of wire meshes or wire nets which are also made from heavy-duty steel wire. Compression claws of this type are considerably lighter in weight by comparison with ordinary compression claws. 

1. Compression claw for connecting wire meshes or wire nets which consists of a corrosion-protected wire and has two legs (12, 13) projecting away from a rounded base (11), enclosing each other at an apex angle (α) which are each provided on their free end with a hook (16, 17), the two hooks being oriented towards each other, characterised in that the legs (12, 13) lie in two planes enclosing an angle (β), such that both hooks (16, 17) can move past each other when the compression claw closes.
 2. Compression claw according to claim 1, characterised in that the wire is a heavy-duty steel wire.
 3. Compression claw according to claim 1, characterised in that the diameter of the wire is preferably 3 mm and the apex angle (α), the radius (R₁) of the base interior and the radius (R₂) of the hook interior are selected such that in each case two wires of the meshing of the wire meshes or wire nets to be connected together of a defined diameter, for example 3 mm, can be grasped when the compression claw (10) closes.
 4. Compression claw according to claim 3, characterised in that the radius (R₂) of the hook interior is smaller than the wire diameter of the compression claw and moreover is the same as or smaller than the radius of the wire of the meshes to be connected.
 5. Compression claw according to claim 1, characterised in that the apex angle (α) is 60°, with both legs (12, 13) being arranged at an angle of 14° with respect to each other immediately in front of the hook (16, 17), so that they enclose an apex angle of 32° in this area.
 6. Compression claw according to claim 1, characterised in that both legs (12, 13) lie in two planes enclosing an angle of approximately 8° with each other.
 7. Compression claw according to claim 1, characterised in that the wire used is the same heavy-duty steel wire as in the wire meshes or wire nets to be connected together, while its nominal tensile strength is preferably at least approximately 1770 N/mm².
 8. Device for closing compression claws (10) for wire meshes or wire nets according to claim 1, characterised by a clamping device (25) functionally linked with a drive and clamp elements (30, 31) for the closure of individual compression claws (10), in which the compression claws (10) can be individually positioned before closure.
 9. Device according to claim 8, characterised in that the clamping device (25) is assigned to a receiving part (22) which can be attached to a commercially available drill (21), while at least one of the clamp elements (30, 31) can be driven by the drill spindle (27) via a step-down gear (26).
 10. Device according to claim 9, characterised in that the clamp elements (30, 31) are formed, firstly by a stationary clamping jaw (30) and secondly by a pivotable carrier element (31), the latter being provided with a toothed segment (50) via which, in co-operation with a toothed counter-segment (51) drivable by the step-down gear (26), and can be pivoted in a direction of rotation (D₁) effecting the closure of the compression claw (10) positioned in the clamping device (25).
 11. Device according to claim 10, characterised in that the carrier element (31) can be pivoted back into an initial position after the completion of the toothed engagement of the two toothed segments (50, 51) by the elasticity of the compression claw (10), supported by an additional spring.
 12. Device according to claim 10, characterised in that the respective compression claw (10)—with its base interior enclosing a peg (53) coaxial with the swivelling axis (A) of the carrier element (31)—is positioned by firstly resting on a ring magnet (54) coaxial to the peg (53) and secondly on a further magnet (55) assigned to the stationary clamping jaw (30).
 13. Device according to claim 9, characterised by a magazine (23) for a number of post claws (10) which can be fed individually out of the magazine (23) of the clamping device (25) by means of a feed device (24).
 14. Device according to claim 13, characterised in that the feed device (24) has a manually operable ram (34) co-operating with a spring (35) and carrying the respective compression claw (10) to a magazine outlet (38).
 15. Device according to claim 14, characterised in that the compression claws (10) are arranged in alignment with each other in the magazine (23) and movable towards the magazine outlet (38) under the action of a spring (41).
 16. Device according to claim 13, characterised in that the magazine (23) and the feed device (24) form part of the attachment part (22) which can be attached to the drill (21), while the respective compression claw (10) can be fed by means of the feed device (24) into a feed plane of the clamping device (25) which is parallel to a drive axle (27 a) connectable to the drill spindle (27).
 17. Device according to claim 16, characterised in that the magazine (23) has a part (37) parallel to and at a distance from the feed plane, to which a reversing part is attached, by which the compression claws (10) are fed to the magazine outlet (38) lying directly above the feed plane and are brought into the feed position.
 18. Device according to claim 17, characterised in that the compression claws (10) located directly at the magazine outlet (38) are held by a magnet until the impact of the ram (34) and thus the other compression claws (10) are secured against falling out of the magazine (23).
 19. Device according to claim 13, characterised in that the magazine (23) has a guide channel (45) corresponding in cross-section to the external form of compression claws (10) and a retaining element (48) securing the compression claws (10) in the guide channel (45) against falling out.
 20. Device according to claim 19, characterised in that the guide channel (45) has two side walls (46, 47) enclosing an angle (α), where the angle (α) corresponds to an apex angle of the compression claws (10) in the original state, and the retaining element (48) projects centrally between the side walls (46, 47) of the guide channel (45) and between hook-shaped ends (16, 17) of the compression claws (10). 